Report construction



25, 19451? D. L. NEWKIRK ET AL 2,391,439

' RETORT CONSTRUCTION Filed Aug. 11, 1945 2 sheets-shee t 1 E E '.Ensi,ofn v INVENTOR.

D.L.Nefilrirlc I Dec. 25, 1945. D. NEWKIRK ET AL" 2,391,439

" RETORT CONSTRUCTION v I FiledAug. 11, 1943 2 Sheis-Sheet 2 E D.L.Newkirk E.E.Ensi d n IN VEN TOR.

I- NITEDF T T Es PATENT OFFICE RE'I'ORT ooNs'mno'riou Daniel L. Newkirk, 'Inkster, and Elbert E. Ensign, Ypsilanti, Mich., assignors to FnrdMotor Compant, Dearborn, Mich, a corporation of Delaware 7 Application August 11, 1943, Serial No. 498,210

' 4 Claims. (chase-15) This invention relates to retort tube furnaces; and, more particularly, to a closure and seal to be used in connection with these furnaces.

The structure of the invention comprises a device to be used in connection with multitube retort furnaces as an end. closure and vacuum seal which has the advantages of rapid installation and removal and of being applicable to a plain retort tube section without provision of auxiliary seals or specially finished surfaces. Furnaces of this type have an externally heated tube containing a charge which undergoes chemical decomposition with the formation of certain gaseous products which are thereafter condensed to solid form; and are ,used'in'the reduction of magnesium ore to obtain metallic magnesium as well as the smelting of other'metals under similar conditions. The retort itself consists essentially of a metal tube supported in the heating chamber (in the present instance, the chamber contains a liquid heating medium as described in copending application Serial No. 454,580) having a portion extending from the chamber which is at a lower temperature and served as the condensing portion of the retort. In the smelting of magnesium, magnesium-bearing dolomitic material is mixed with ferrosilicon and formed in briquettes which are charged into the tube. The retort is closed and evacuated; and the charge brought to the reaction temperature. Gaseous magnesium is formed as the result ofthe chemical decomposition which ensues andis drawn toward the extending portion of the tube by flow established by the evacuating pump. Since this portion is maintained below the condensation temperature of the gaseous magnesium, magnesium metal in reguline form is deposited there. When the reaction is complete the tube is opened and the metal will be found localized in the condensation portion, the exhausted charge remaining in the chamber portion of retort tube. These materials are. removed and the process repeated. It will be apparent that this process is equally adaptable .to anymetal which may be formed in the gaseous stage during smelting. I

The conditions of reactiondemand that a prac tically complete vacuum be maintained in the tube to restrain the reversibility of the reaction; and this, in turn, necessitates highly eflicient sealed closures at the ends of the tube. However,

the closure must be readily removable for charg finished sealing surface on them.

high temperatures are maintained in the tube during the reaction and as a consequence the tubes may in time collapse or fail, even though submerged in the silicate bath, and require replacement. As described in our copending application Methods of replacing retorts, Serial 498,212, filed August 11, 1943, it is possible to replace the tube without draining the furnace or shutting off production of the other tubes immersed in. the bath. However, when the procedure of pulling a new tube through while attached to the old tube is followed, the tube ends are necessarily defaced to the extent that it would not be practicable to maintain a highly It would be difficult to machine such a finish in installed position, and therefore it is of particular consideraticn'thatthe closure be effective on comparafinishing of the tubes to which it is applied, and

' it is so designed that variations in over-all length A of the tube do not affect the security of the steel.

Another advantage is that the seal is well nigh perfect in so far as vacuum is concerned and of such durable nature that it may be reused almost indefinitely. Another advantage is that it permits the use of articulated sealing means serving a number of tubes and reducing considerably the labor of opening and closing the tube after each successive operation of the retort. Yet another advantage is that the seal is, to. all intents, selfactuating.

With these and other objects in view, the invention consists in the arrangement, construction and combination of the various parts ofthe improved devlce as described in the specification, claimed in the claims and illustrated in the accompanying drawings in which:

Fig. 1 is a side view of the exterior portion of the retort tube, taken on the line 'l--|' of Fig. 2.

Fig. 2 isan elevation of a portion of the face of the retort furnace showing a multiple tube arrangement. 7

Fig. '3 is a longitudinal section through the condensation portion of a retort tube.

v Fig. 4 is a fragmentary sectional view, on an the front wall II and the retort tubes IZWhich project into the chamber are shown. A solidified seal I3 between the wall II and the retort tube I2 prevents leakage of the molten material within the furnace. Each tube I2 includes a heavy furnace tube section I4 and a lighter condensation tube section I5 welded to it. An airtight closure precise over-all length is not an important factor. Finally, sealing is accomplished merely by lowering the cover into engagement with the gasket.

and is perfected and maintained solely by the vacuum in the tube obviating the usual clamps or retainers.

Some changes may be made in the arrangement, construction and combination of the various parts of the improved construction without departing from the spirit of the invention and it is the intention to cover by the claims such changes as may be reasonably included within the scope thereof.

is provided through a cover I6 having a flared flange I1 and hingedly supported by an evacuation pipe I8 which includes an extensible bellows section I9 on the exhaust header 20. The header is closed at one end 2! and has a pintle 22 pivoted on the support 23. The other end of the header.

is joined by a union 24 to the exhaust line "25 which serves as the opposite support. A handle 26 facilitates rotation of the header and its associated covers to the position shown in dotted line in Fig. 1 when the union 24 is loosened.

The outer end of the condensation section I5 is surrounded by water jacket 2? having the connections 28 which fix it in place relative to the wall II of the furnace. The interior of the condensation tube section I5 receives the condensing sleeve 35 which defines the condensing chamber 30 separated by an apertured heat dam 3| from the interior of the retort proper and closed at the other end by a cellular diaphragm 32, the inner.

surface 33 of which is traversed by a conduit 34 laid along the lower side of the sleeve. The outer diaphragm surface 36 is centrally apertured so as to permit the passage of gases from the interior of the retort to the space defined by thecover I6 and thence through the evacuationpipe I8 to the exhaust system. The purpose of this structure, as more fully explained in the copending application ntitled Condensation device for retorts,- Serial 498,209, filed August 11, 1943, permits the reverse flow of the gaseous magnesium entering the condensation chamber from the retort and insures complete condensation of th reaction products and especially provides for selective condensation of the various gaseous components.

The seal between the cover I6 and the condensation tube section I 5 is effected through the agency of a rubber ring gasket 3'! which, as best shown in Fig. 4, runs around the outer surface of the tube section I5 between the Water jacket 21 and the flared flange I! of the cover I6. The ring gasket may be of circular or triangular cross section, that shown in Fig.4 being normally circular but deformed under the joint influence of the flange, water jacket and tube. It will be noted that the exterior of the tube section I5 is perfectly plain and that the inner diameter of the crown 38 of the cover is just slightly larger than the outer diameter of the tube I 5. It is thus apparent that the over-all length of the tube need not be held to close limits even though the covers are fixed in relative closing position by reason of their mounting, as shown in Fig. 2. Employing such a cover mounting with conventional seals would require that the sealing surface of the tube be positioned exactly to co-operate in the selected position with the cover. This is obviously impracticable under the conditions in which the retort is operated due to the variation in tube length encountered. With the present mounting, a wide range of usable sealing. surface is presented, and since the cover can fit over the tube, if need be,

' The invention claimed is: e 1. In'a retort furnace, a furnace, a tube supported therein and having an end extending therefrom, a circumferential abutment thereon, an exhaust collection system mounted outside of said furnace andsubstantially aligned with the end of said tube, an exhaust header pivotally mounted on said exhaust system, an evacuation tube fixedly secured to said header andextending therefrom, a cover fixedly secured to the lower end of said evacuation tube, expansible means in said evacuation tube intermediate said header and said cover, a swingable connection between said evacuation system and said header whereby said cover may be swung into and out of engagement with the end of said tube, and compressible sealing means between said tube and said cover and said abutment adapted to be compressed therebetween solel in response to atmospheric pressure when the interior of said tube is evacuated.

2. In a retort furnace, a furnace, a pluralit of tubes having their mid portion supported in said furnace and ends extending therefrom, the ends of said tubes being in substantially common alignment, an exhaust collection system erected forwardly of said furnace in substantially the plane of said ends and including a rotatably mounted transverse header pipe extending across the face of said furnace above said tubes, covers for the ends of said tubes supported on said header pipe and adapted to be swung into and out of engagement with said tubes as a unit with said header pipe, a water-cooled abutment on each tube spaced a short distance inwardly from the end thereof, and a compressible ring gasket disposed on the outer surface of each tube between saidabutment and the end of said tube and adapted to be compressed between said abutment and said tube surface and the inner surface of said cover to effect a vacuum tight seal therebetween.

3. In a tube retort furnace; a furnace structure, a tube supported in said furnace and having a portion extending therefrom, the portion of said tube within said furnace serving as a reaction zone, and the portion extending therefrom serving as a condensation zone, an abutment surrounding said tube adjacent its outer end and fixed relative to said furnace, means to cool said abutment, a removable cover for the end of said tube extending from said furnace, said cover having. a peripheral obliquely flared flange adapted to overlie the outer surface of said tube and to cover the end thereof, a ring gasket of readily compressible materialsurrounding said tube and positioned between said abutment and said peripheral flange and the outer surface of said tube, said ring gasket being compressed between said abutment and said flange on said cover and said tube, when said cover is in position to form a vacuum-tight seal between said cover and said abutment and said tube.

4. In a retort furnace, a furnace, a tube supported therein and having an end extending therefrom, a circumferential abutment thereon,

an exhaust collection system mounted outside of said furnace adjacent the end of said tube, an

exhaust header communicating with said exhaust system, an evacuation tube'communicating with said header and extending therefrom, a cover fixedly secured at lower end of said evacuation tube, a swingable connection between said evacuation system and said evacuation tube whereby said cover may be swung into and out of engagement with the end of said tube, and'compressible sealing means between said tube and said cover and said abutment adapted to be compressed therebetween in response to atmospheric pressure when the interior of said tube is evacuated.

DAN L. NEWKIRK, EIBERT E. ENSIGN. 

